Kuther, Tara L., editor
Thomson, 2006
Buku Teks
Sternberg, Robert J., author
APA, 2000
Buku Teks
Johnson, George
Julian Messner, 1969
Buku Teks
Cagle, Ronald B., author
[American Management Association, ], 2005
eBooks
Matthews, Janet R.
Allyn and Bacon, 1997
Buku Teks